[IS-elements and transposons: new linkage of genes within bacteria (author's transl)].

IS-Elements are unique DNA sequences occurring in the DNA of E. coli and its chromosomes. They can be transposed within or between chromosomes in the same cell. Integration into a gene causes mutations and polar effects on adjacent genes. IS-Elements are integration sites for plasmids into chromosomes. IS-Elements also serve as parts of transposons (DNA structures capable to be transposed from one chromosome to another and carrying a gene for the resistance to an antibiotic or heavy metals).